1. Field of the Invention
The present invention relates to the provision of call-waiting services on a telecommunications network.
2. Related Art
Call-waiting services have been developed and deployed on public switched telephone networks (PSTNs) to provide the option of receiving a call from a third party during the course of an existing call. If the user has subscribed to a call-waiting service, then the network responds to the call from the third party by alerting the user to the fact that there is another caller waiting to contact them. Typically this is done by transmitting a distinctive in-band analogue tone from the network to the user. The user then has the option of interrupting the first call and speaking to the other caller.
It is increasingly common for PSTNs to be used for dial-up data connections. For example, a personal computer and a modem might be used as a data terminal to establish a dial-up connection with an on-line service or an Internet services provider (ISP). However, it has been found that there are serious technical problems with the interaction between conventional call-waiting services and dial-up data connections. The data connection is generally carried over a digital signalling channel in the form of frequency-shift keyed or phase-shift keyed tones transmitted to/from the modem. If a conventional call-waiting service transmits its own analogue tone to the user while the data connection is on-going, then this tone corrupts the signalling channel and will usually cause the connection between the user and the data services provider to be lost.
U.S. Pat. No. 4,995,074 describes the problems outlined above. This patent proposes a solution which involves placing a second computing system (termed xe2x80x9cthe interfacexe2x80x9d), comprising a microprocessor, memory, registers and analogue telephony circuitry, between the telephone network and the modem. This system then intercepts incoming call waiting signals, and communicates control signals between the network and the personal computer. In this way the system avoids disruption of the modem connection by the call waiting signal, and is able to offer the user choices as to how an incoming call is handled. However, since this solution relies upon the introduction of the second computing system at the customer premises, it is expensive and has not found commercial acceptance.
According to a first aspect of the present Invention, there is provided a method of operating a telecommunications network comprising:
(a) establishing a dial-up connection via the telecommunications network between a user data terminal and a data services provider;
(b) transmitting a data channel over the dial-up connection; and
(c) transmitting a call waiting signal on the data channel to the user when a call is made to the user by a third party.
The present invention provides a method of operating a telecommunications network which not only avoids the disruption of data connections associated with conventional call-waiting services, but also makes the call-waiting functionality available to users while their call to a data service provider is in progress. This is achieved by transmitting the call-waiting signal on the channel used for the data connection. The call-waiting signal is in this way integrated with the data connection, instead of disrupting it. Moreover, the signal is in a form which facilitates automatic handling of the response to the signal by programs running at the user data terminal and/or at the data services provider. Once the call-waiting signal has reached the user, then, as with the conventional call-waiting services, the user can choose to continue with the existing call, or may interrupt the calf to speak to the new caller. By contrast with prior art systems, the invention requires no additional hardware at the customer premises, nor does it require any modification to the modem.
Preferably, step (c) includes:
(i) diverting to the data services provider calls which are intended for the user; and
(ii) generating at the data services provider, in response to the receipt of an incoming third party call, the call waiting signal for transmission to the user.
It is found that a particularly effective approach to implementing the invention takes advantage of the existing call diversion functionality available on most exchanges. Once the user has established the dial-up connection with the data services provider. other calls for the user are diverted to the data services provider which can then generate an appropriate call waiting alert for transmission over the data channel to the user.
The method may optionally include a step, subsequent to the transmission of the call-waiting signal, of interrupting the connection with the data services provider and establishing an in-band connection between the user and the third party. In this case preferably the data services provider :s arranged to suspend any on-going data transaction with the user data terminal, and to resume the data transaction when the connection with the data services provider is re-established after the completion of the call from the third party.
Alternatively or in addition, the method may include establishing a voice connection between the third party and the user data terminal over the data channel.
Preferably the method includes generating at the data terminal, in response to receipt of the call waiting signal, a message alerting the user to the third party call. Advantageously, the handling at the data terminal of the call waiting signal uses the user interface of the data terminal both to display an xe2x80x9calertxe2x80x9d message, which may include the calling line identity (CLI), and also to offer the user options for how the call is to be handled. The data terminal may then generate and return via the data channel to the data services provider a signal identifying the selected option.
According to a second aspect of the present invention, there is provided a telecommunications network arranged to provide a dial-up connection between a user data terminal and a data services provider, in use a data channel being transmitted over the dial-up connection, characterised by means for transmitting a call-waiting signal on the data channel to the data terminal in response to a call from a third party.
According to a further aspect of the present invention, there is provided a method of operating a call waiting system comprising:
(a) receiving from a telecommunications network a signal indicating a call has been made by a third party to a user, the said user having a current dial-up connection between a user data terminal and a data services provider; and
(b) in response to the said signal generating a call waiting signal and transmitting the said call waiting signal on the data channel to the user.
The call waiting system may form part of a data server at the data services provider. Alternatively it may comprise a computer dedicated to this task, and may be located remotely from the data services provider. In this case it may output the call waiting signal, e.g. onto the internet, addressed to the user, for transmission via the data services provider.
The invention also encompasses data terminals and data servers configured for use with the network of the second aspect.